1. Field of the Invention
The present invention relates to a method of manufacturing an inductor preferably for use in a mobile phone, for example.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 11-204336 and Japanese Unexamined Patent Application Publication No. 2005-109097 disclose methods of manufacturing an inductor.
According to a manufacturing method of the related art, PET films and dummy substrates are used as base materials, and a photosensitive insulating paste is printed on the base material. Then, the photosensitive insulating paste is exposed (developed and additionally exposed as necessary) and dried to form an insulating layer. The photosensitive conductive paste is printed, exposed, developed (additionally exposed as necessary), and dried to form a conductor pattern. Next, the photosensitive insulating paste is printed, exposed, developed (additionally exposed as necessary), and dried to form an insulating layer and a viahole. A conductor pattern and an insulating layer with a viahole are alternately laminated, thereby forming a laminate. Next, this laminate is divided to form small chips having a desired chip size. Then, the base substrate is removed from the chips, and the chips are fired. After external electrodes are formed on end portions of each chip, plating is performed on external electrode portions to complete the formation of a chip-shaped inductor.
However, the above-described manufacturing method of the related art has the following problems.
FIG. 21 is an exterior view of an inductor of the related art. FIG. 22 is a schematic sectional view showing an inductor being transported.
As shown in FIG. 21, in a manufacturing method of the related art, after a chip 100A of an inductor 100 is formed, since external electrodes 111 and 112 are formed on both ends of the chip 100A, it is not possible to sufficiently maintain the volume of the chip 100A as desired. For example, when an inductor of a specified size 0603 (a vertical size of about 0.6 mm, a horizontal size of about 0.3 mm, and a height of about 0.3 mm) is to be manufactured, the size of the fired chip 100A is set to a vertical size of about 0.56 mm, a horizontal size of about 0.26 mm, and a height of about 0.26 mm, and the external electrodes 111 and 112 are formed on both end portions of the chip 100A, thereby obtaining a specified size 0603. For this reason, the size of the chip 100A is reduced, a limitation is imposed on the size of a coil to be formed inside thereof, and an inductance value of a sufficient magnitude cannot be obtained.
Furthermore, as shown in FIG. 22, since a step difference corresponding to the thickness of the external electrodes exists between the surface of the chip 100A and the external electrodes 111 and 112, a problem arises when a very small inductor 100 is to be mounted. That is, as indicated by the dashed line in FIG. 22, when the size of the inductor 100 is considerably larger than the diameter of the suction nozzle 200, even if a step difference exists between the surface of the chip 100A and the external electrodes 111 and 112, air leakage does not occur. Therefore, it is possible for the suction nozzle 200 to strongly suck the inductor 100 and to transport it to a desired mounting location. However, as the size of the inductor decreases, when a very small inductor 100 of a specified size 0603 is to be transported, as indicated by a solid line, the suction nozzle 200 spans the external electrodes 111 and 112, a gap occurs between the suction nozzle 200 and the surface of the chip 100A, and air leakage occurs. For this reason, the suction nozzle 200 cannot strongly suck the inductor 100, there is a risk that the inductor 100 may be dropped while being transported, and the inductor 100 may be mounted at a location that is deviated from a desired mounting location.